1. Field of the Invention.
This invention relates to a new and improved intermediary adapter-connector to be interposed between printed circuit boards and devices such as encapsulated integrated circuit components. More particularly the invention relates to an adapter having holes to receive the pins of a device and to establish electrical contact with such pins, and electrical traces establishing electrical contact between such pins and pads located on the adapter for electrical contact with corresponding contacts or pads on a printed circuit board.
2. Description of Related Art.
Printed circuit boards (PCBs) are of two general types. The first is a plug-in type wherein devices having multiple pins plug into holes in the PCB. Electrical conductive traces interconnect the pins either with leads of other components on the board or with other electronic circuitry. This type of board has the advantage of providing quite reliable connections. The other type now becoming more common is the so-called "surface mount" PCB, wherein the pins of the devices are considerably shorter and engage pads of solder (for example) positioned on the PCB. While in general less area is required by a surface mount arrangement than would be required when a PCB of the first type is used, the connections have not been as reliable. Further such connections have not made it possible to remove devices once they have been soldered in place. However, because this type conserves board space, uses of the same are preferred in many situations. The present invention has the advantage of enabling use of devices having the longer pins devised for plug-in type PCBs with surface mount PCBs.
Thus the present invention provides a bridge between surface mount and through-hole technology. Thus the user may adapt a surface mount board to use through hole type devices.
A component-carrying adapter for a chip carrier socket is disclosed in U.S. Pat. No. 4,872,844. Such an adapter has a substrate carrying one or more components which are connected by plated circuitry to comprise a member securable between a chip carrier socket and a printed circuit panel. Some of the interconnections are interrupted by dielectric material of the substrate and are blind plated holes connected to components. Post members are insertable into the blind plated holes and are matable with plated through holes of the panel. Such an adapter has different structure and function from the adapter herein described.
Various problems have arisen in the use of surface mounted PCBs which are solved by the present invention. One such problem is the matter of reliability of the electrical contact, that is, it has been difficult to inspect the contact between the pins of the socket for the device and the pads on the board. This is particularly true when there are contacts hidden by the socket or the device. In the present invention the locations of the pads are preferably at peripheral edges of the adapter so that their electrical connection to the board can be visually inspected.